Postreplication repair of DNA in UV-irradiated mammalian cells.

Some current controversies concerning the mechanism of postreplication repair in mammalian cells are discussed. We have found that two xeroderma pigmentosum cell lines normal in excision-repair are abnormal in postreplication repair. The rate of postreplication repair is slower than that in normal cells and is caffeine sensitive. In normal human fibroblasts, caffeine has little effect.